From: Martin Jambon <martin_jambon@emailuser.net>
To: Jeffrey Cook <jeffrey.j.cook@gmail.com>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Records with default values
Date: Wed, 23 Mar 2005 12:25:44 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.44.0503231150001.1304-100000@localhost> (raw)
In-Reply-To: <88707140050323114156bcb9fb@mail.gmail.com>
On Wed, 23 Mar 2005, Jeffrey Cook wrote:
> What I would like is the following:
>
> type bob = {
> foo : string ;
> bar : int := 0 ;
> }
>
> let x = { foo = "hello" }
I would go for a "create_bob" function with labelled arguments, some of
them being optional:
let rec create_bob ~foo ?(bar = 0) () =
{ foo = foo;
bar = bar }
Implementing a syntax extension that defines "create_bob" automatically is
typically something that can be done with Camlp4 :-)
It supports recursive type definitions such as:
type t = { x : t option = Some { x = None } }
or even (since create_t is recursive):
type t = { x : t option = Some (create_t ~x:None ()) }
which would be expanded into:
type t = { x : t option }
let rec create_t ?(x = Some (create_t ~x:None ())) () = { x = x }
Martin
--
Martin Jambon, PhD
http://martin.jambon.free.fr
prev parent reply other threads:[~2005-03-23 20:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-23 19:41 Jeffrey Cook
2005-03-23 20:25 ` Martin Jambon [this message]
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